/Engine/Source/Runtime/Core/Public/UObject/WeakObjectPtrTemplates.h
SetKeyFuncs for TWeakObjectPtrs which allow the key to become stale without invalidating the set.
template<typename ElementType, bool bInAllowDuplicateKeys> struct TWeakObjectPtrSetKeyFuncs : public [DefaultKeyFuncs< ElementType, bInAllowDuplicateKeys >](API\Runtime\Core\Containers\DefaultKeyFuncs)